How Substance Use Affects the Brain

Substance use can be a root cause of adverse effects in your life. Substance use can significantly harm your physical, mental, and social well-being depending on the severity of use and potential for addiction.

The core of these concerns lies in the relationship between substances and the brain. Let’s take a look at that relationship, shall we?


Substance use disorder is a disease that impacts one’s ability to control the use of a substance.

The Substance Abuse and Mental Health Administration (SAMHSA) defines it as occurring “when the recurrent use of alcohol or other drugs causes significant impairment, including health problems, disability, and failure to meet major responsibilities at work, school, or home.”

Risk factors for addiction include genetics, social and physical environment, and lifestyle.


When the chemical makeup of substances like stimulants, opioids, alcohol, and sedatives enter the brain, it can often cause a loss of control and trigger cravings. These cravings stem from how the substance interacts with the brain’s reward system. Our brains begin to think we need the substance and cannot function without it. This

When someone lives with an addiction, their brain persistently craves the same rewarding sensation of a particular substance, making addiction challenging (but not impossible) to overcome.


People who suffer from substance use disorder often find themselves addicted because of the positive, euphoric sensations experienced in the short term.

Effects on the brain vary from substance to substance. For instance, high amounts of alcohol can lead to headaches and slurred speech, whereas high doses of marijuana can affect your time perception. Certain drugs, such as LSD, can cause hallucinations and synesthesia.

There are short-term effects that are common in all substance use, though. Such as:

  • Impaired judgment
  • Increased reaction time
  • Impaired coordination
  • Impaired judgment and decision-making
  • Inattention
  • Mood changes
  • Increased inhibition
  • Impulsivity
  • Coma

All these short-term effects on your brain can transition into harmful long-term impacts.


Unfortunately, substance use also has significant long-term effects on the brain. These effects become more substantial depending on your age when you began using and the length of use. Substance use can seriously damage parts of your body beyond the brain, particularly your internal organs, and it can also negatively impact your personal social life.

Like short-term effects, long-term effects can vary from substance to substance, but some common effects will target your brain no matter the drug you are using. For example:

  • Addiction
  • Other mental health disorders, such as depression and anxiety
  • Brain shrinkage
  • Permanent mood or personality changes
  • Higher risks of dementia

No matter the effects that substance use has had on your brain, you should still seek help if you are struggling. As noted, substance use can cause serious issues but is not limited to the brain.

That said, substance use disorder is possible to overcome. Don’t be afraid to reach out today for help fighting this disease. The support you’ve longed for awaits.


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